Wax emulsion polishing composition containing silica



Patented May 27, 1952 WAX EMULSION POLISHING COMPOSITION CONTAININGSILICA Ralph K. Iler, ClevelandHeights, Ohio, assignor to E. I. du Pontde Nemours & Company, Wilmington, Del., a corporation of Delaware NoDrawing. Application September 20, 1947, Serial No. 775,375

8 Claims. (Cl. 10 6-10) This invention relates to novel wax compositionsand more particularly to compositions which comprise aqueous dispersionsof a wax and colloidal silica and which when applied to surfaces producea film having improved slip-resistance without loss of luster.

This application is a continuation-in-part of my application Serial No.699,087, filed September 24, 1946, for Chemical Compositions, nowabandoned.

Wax coatings are commonly applied to the surfaces of furniture,automobiles, and wood, asphalt tile, and linoleum floors for the purposeof imparting a pleasing, lustrous appearance and a protective filmagainst dirt and moisture. Suspensions of such waxes as carnauba,montan, candelilla, beeswax and paraffin have been used for this purposeand have been applied in such forms as aqueous dispersions andsolvent-containing pastes. Some of these compositions are of theself-polishing type, that is, they are applied as a suspension of wax ina carrier such as water and dry to a polished appearance without furtherrubbing.

Many wax polishes which have been proposed give coatings of pleasingappearance but which unfortunately are lacking in resistance toslipping. Such formulations, when applied to lineoleum floors, forinstance, give coatings which are not entirely safe to walk upon, inthat leather shoe soles slide quite easily upon them. Similarly,

freedom from loss of luster is particularly important in the case of theself-polishing wax polishes. Moreover, inclusion of colloidal silicaaccording to the invention has the further ad vantage of improving theluster of films obtainable from certain wax suspensions. Thesuspensions, without the colloidal silica, ordinarily give coatings ofpoor luster which are herein referred to as normally low-glosscoatings." Such compositions are used despite their poor luster becausetheir ingredients are relatively cheap, and the silica inclusiontherefore is particularly desirable because it renders thesecompositions competitive with more expensive high gloss products.

The improvement in slip resistance effected by inclusion of colloidalsilica in a wax coating will be understood to mean the increase in forceparallel to the plane of the wax coating required to cause an object,such as a shoe sole, to slide rugs placed upon floors waxed with suchmaterials slide readily when stepped upon and constantly are a hazard.

Efforts have been made to correct this lack of slip-resistance byincluding other materials, for example, ground feldspar, in the waxformulation. Such inclusions, however, often result in an impairment ofthe luster and pleasing appearance of the wax-coated surface.

Now according to the present invention it has been found that byincluding colloidal silica in aqueous wax dispersions novel compositionsare produced, from which coatings may be made having a markedimprovement in slip-resistance without any loss in luster and with animprovement in the luster of normally low-gloss coatings.

The invention has application to such aqueous wax dispersions as therelatively dilute wax suspensions of the self-polishing type, the moreconcentrated water-containing wax pastes, and other such compositions inwhich a wax is dispersed in an aqueous medium. The improvement inslipresistance is, of course, particularly important in the case offloor waxes. The advantage of over the wax coating, as compared to thesimilar force for the coating without the silica inclusion.

The improvement in luster of normally low gloss coatings occasioned byinclusion of colloidal silica refers to the increase in lightreflectance thus obtained. It will be understood that this effect ismost pronounced for coatings which without the silica have the poorestluster.

The term wax as used herein will be understood to include not only thenaturally occurring materials composed largely of fatty acid'esters ofhigh molecular weight monohydric alcohols, such as carnauba, candelilla,and beeswax but also other organic, water-insoluble materials Which havethe physical character of waxes. This is in accord with general usage inthe art, as is illustrated in an articl entitled Waxes in Industry-I byA. H. Woodhead, in Paint Manufacture, vol. 17, page 40 (1947) It hasbeen the practice in recent years to in clude in the term wax thosesubstances which bear-some physical resemblance to any of the naturalwaxes, including paraifins and ozokerites. This definition is moreuseful since the inception of a large range of synthetic products ofwax-like appearance and physical behaviour, and it is due to thisconception that such substances as naphthalene chlorides, polyethylenes,many higher hydrocarbons, and even glyceride esters are now termed waxesand are used industrially as waxes. A wax, then, is a substance, usuallycomplex, which is of amorphous or microcrystalline structure and usuallylacking excessive tack at normal temperature, and which melts fairlysharply to give a (usually) mobile liquid at a temperature but littlehigher than its normal meltingpoint. This definition largely excludesresins and the common simpler crystalloidal chemicals.

While this definition largely excludes resins it will be noted thatthere is a group of high molecular weight polymeric materials commonlycalled synthetic waxes which have wax-like physical properties and henceare included within the definition. It has been found that emulsions or,

more properly, suspensions of such high molecular weight polymericwaxes, in combination with colloidal silica, particularlysodium-stabilized colloidal silica, provide improved waterproofing andpolishing compositions in accordance with this invention.

The waxes thus fall into three general categories, namely, the esterwaxes mentioned above which are usually naturally occurring either asplant exudations or animal excreta, the hydrocarbon waxes, oftenreferred to as mineral waxes, including montan, ozokerite, ceresin, andparafiin, and synthetic polymeric waxes, including condensation productsof hardened castor oil or octadecanedicl with boric acid, monobasiccarboxylic acid esters of perhydrogenated novolac, polyethylene adipate,telornerization products of y e and dichloracetic acid, andethylene/brornacetic acid. The term novolac as used herein refers tolinear, thermoplastic, phenol-formaldehyde polymers having the typicalformula CsH3(OI-I) CHzCsHflOH) CH2 as described in Chemistry ofCommercial Plastics by R. L, Wakeman, Reinhold Publishing Corp., 1947,at p. 118. A carboxylic acid ester of perhydrogenated novolac thus is anovolac which has under one substantially complete hydrogenation of thebenzene rings to give cyclohexane rings and the hydroxyl on each ring ofwhich has been esterifled with a carboxylic acid. The termtelomerization products refers to polymers of ethylene wherein thepolymerization has been terminated by such agents as dichloroacetic acidor bromacetic acid, as described more fully in Example 11, below.

The amount of a wax used in anaqueous dispersion of this invention maybe widely varied depending upon the particular use for which thecomposition isintended. When the composition is in paste form, as, inthe rub-to-polish type, the proportion of wax may be from 20 to 40% byweight of the total. On the other hand, in the a ueous wax dispersionsof the self-polishing type, in which the colloidal silica isparticularly effective, the proportion of wax may be from about to byweight of the'total.

The term colloidal silica as used in describing this invention refers tosilica in the form of particles of colloidal dimensions, that is,particles having an average size not exceeding about 100 millimicronsnor less than about 1 millimicron. It is particularly preferred to usecolloidal silica having an average ultimate particle size less thanabout millimicrons, that is, 0.03 micron. By ultimate particlesize ismeant the average size of particle present when the solution is dilutedto about 0.1% SiOz with water and dried in a very thin layer deposit.

The silica particles will not necessarily be present as anhydroussilicon dioxide but rather. may, be in a hydrated form associated withvarious proportions of water. Thus, partially dehydrated silicic acidwould come within the term silica as herein used.

The colloidal silica may be prepared by methods with which the art isalready acquainted. Thus it may be prepared by neutralizing a sodiumsilicate solution with an acid and dialyzing out the sodium salt. Suchsolutions of silica, however, are characteristically unstable and areimpractical to use.

More recently there have become available relatively concentrated silicasols which have sufficient stability to make their use in waxdispersions practical. Such a sol may be prepared, for instance, byredispersing a silica gel with an alkali as described in NeundlingerPatent 1,835,420 or White Patent 2,375,738. According to these methodssilica sols which are relatively stable and which contain up to about18% SiO2 may be prepared in a suitable form for use in aqueous waxdispersions. Unfortunately such dispersions contain a minor proportionof very high molecular weight colloidal silica which tends to give aheterogeneous solution.

Another commercially available colloidal silica solution which maybeused is characterized by having an .8102 content of about 15%, aviscosity of 27.6 centipoises at 25 0., and the following chemicalanalysis:

It is particularly preferred to use colloidal solutions of silica inwhich the silica particles are characterized by having alkali ions sodisposed on the surface of the particles as to prevent condensationbetween the particles by oxolation in an aqueous solution of aconcentration not exceeding about; 45% $102 by weight. As freshlyprepared, the silicic acid in a silica solution may exist as lowmolecular weight polymers of the theoretical SMOHM; however, acondensation reaction known as oxolation rapidly occurs whereby watersplits out between hydroxyl groups attached to silicon atoms, an Si-O-Si linkage is formed, and a polymer is produced. This process maycontinue indefinitely andin such a manner that the silicic acid solutionrapidly sets upto a gel, the oxolation occurring between externallydisposed hydroxyls, i. e., hydroxyls not already inactivated by beinginwardly located within a siloxa-ne ring or micelle. It has been found,however, that such polymerization is retarded by the presence of a smallamount of combined alkali such as sodium.

A logical explanation for such retardation of thegelling rate of silicicacid solution has been that the sodium ions act as blocking groups byreplacing the active acid hydrogen in a sufficient number of externallydisposed hydroxyl groups to prevent further oxolation in a concentrationnot exceeding about 45% $102. This stabilization may be accomplished byprocesses described in the Bird Patent, 2,244,325. In order to producestable solutions with a minimum of alkali stabilizing agent, thepolymerization of the 'silicic' acid maybe carried to a relatively highmolecular weight so as to produce large molecules or colloidal particleswhich then retain only a small percentage of the reactive hydroxylgroups originally present, and which thus require-only a small amountof. alkali as a stabilizer. On the other hand the polymerization mustnot proceed to the formation of a gel.

A very practical method for producing stabilized aqueous colloidalsilica solutions consists in passing an alkali silicate solution throughan acid-regenerated ion exchange resin as described in theabove-mentioned Bird patent whereby alkali ions are removed from thesilicate and replaced with hydrogen ions. In this instance the alkaliions may be completely removed and then alkali hydroxide may be added tofurnish the necessary alkali ions required as blocking groups.

A particular stabilized aqueous colloidal silica solution which may beused in a composition of this invention is described in the Bird patentat page 2, column 1, lines 12 to 68. As stated in the Bird patent theweight ratio of SiOc to NazO may be as high as from 75 to 100:1 and aslow as :1, but ratios from 30:1 to 80:1 give superior results and arepreferred. The higher the ratio, of course, the lower will be the numberof sodium ions present as blocking groups.

. This disclosure in the Bird patent describes the preparation of anefiiuent from the ion exchanger having a silica content of about 3 to3.5% which maybe evaporated, preferably in a vacuum evaporator to aboutone-half its original bulk thereby raising its silica content to about 6to 6.5%. Even at 6.5% S102 the solutions are too dilute to be shipped,stored, and handled economically and it is preferred to evaporate themto an SiOz content of from 18 to 30%. This may be done in a number ofways and the product obtained will have somewhat differentcharacteristics depending upon the method of evaporation. For instancethe evaporation may be carried out in the batchwise manner at constantvolume, by adding a suitable volume of efiluent from the ion exchangerto the evaporator and adding additional fresh eflluent at the same ratethat water is evaporated oil so that the volume in the evaporatorremains substantially constant. This evaporation may be carried out atatmospheric pressure or even superatmospheric pressure to give a producthaving maximum stability and containing as high as 30 to 35% SiOz. Themolecular weight of the silica is about from 0.6 to 4.0 million and theaverage particle size is well below 30 millimicrons.

An alternative method of evaporation, which gives a product of highermolecular weight but still of colloidal dimensions, may be obtained bycarrying out the evaporation at constant volume but in a continuousmanner. Thus, from a constant volume in the evaporator concentratedproduct is continuously withdrawn and fresh efiluent is added at a ratesufficient to maintain constant volume in the evaporator and to make upthe decrease effected by evaporation and product withdrawal. The productthus obtained contains particles of substantially uniform sizecorresponding to a molecular weight lying in the range of about from 0.6to 100.0 million.

The preferred colloidal silica solutions for use in wax dispersions ofthis invention prepared according to ion-exchange methods as abovedescribed and designated as alkali-stabilized are characterized bycontaining silica particles having an average molecular weight of aboutfrom 0.6 to 100.0 million as determined by light scattering in aqueousdispersion. The theory of the light scattering method for determiningmolecular weight is described in an article by R. Stein and P. Doty,Journal American Chemical Society,

68, 159 (1946). According to this theory, theweight-average-molecular-weight, Mw, is a function of the turbidity,hand the conoentration,

'6 i C, of a polymeric dispersion of solution, according to thefollowing equations:

HC'/'r=1/Mw+2BC'/RT (Equation a) where:

2 321r n dc 3A N n=refractive index in air of the solution.

(Equation b) g =index of refraction gradient between solvent andsolution in terms of g./cc.

)\=wave length in air of light used, in cm. N 6.02 X 10 particles/moleAvogadros number).

With reference to Figure 1 of the Stein and Doty article, the mercurylamp A serves as the light source which is first rendered nonochromatic(5461 A.) by the mounted Corning filters B and then made parallel by acollimating lens C in conjunction with a smell 1.5 cm. diaphragm D.Neutral filters to reduce the intensity of the light during thecalibration are inserted before the diaphragm instead of in the positionE indicated on Figure 1. A semitransparent glass plate E mounted afterthe green filters reflects a small fraction of the beam through anopalescent glass plate F and thence into the photometer K, to becompared visually with the light scattered at by the solution. A squareglass cell G containing the polymer solution is immersed in awater-filled chamber h to reduce reflection at the interfaces. and thewater-filled chamber is surrounded by circulating water for temperaturecontrol. The light reflected at 90 by the solution is transmittedthrough a lens J into the other side of the photometer and compared withthe standard beam. A cone I absorbs the transmitted light by multiplereflection. Readings are taken directly from the dials M on thephotometer.

During calibration only, two neutral, filters are inserted to reduce thelight intensity of the entire incident beam. The calibration is basedeither on a magnesium carbonate surface placed at 45 to the incidentbeam, or on a similarly placed vitrolite surface whose absolutereflectance is known. Readings are taken when matched fields areobtained. The two neutral filters are removed and the block is thenreplaced by a solution of the polymer of known concentration and again areading is taken when the fields are matched. The properties of lightmake it possible to correlate the dial readings obtained during thecalibration with the solution values and to obtain values for absoluteturbidity.

Values for n and for auiatnevr:

be accurate to the fourth decimal place. since the difference betweenthe: refractive index of water and a. 1% S102 solution ranges from only0.0007 to 0.0009, depending on the type of silica.

Values for absolute turbidity obtained by the above photometer readingscan be treated grahpically or by calculation. Concentration/ turbidityis plotted against concentration for four or five points on a givensolution. M may be determined by extrapolation of the best straight linedrawn visually through these points and use of the intercept inEquation. a. More accurate values are obtained by calculating theintercept and the slope by, for example, the method of least squares.

The. alkali-stabilized colloidal silica solutions ihcoporated in thecompositions of this invention are still further characterized byhaving, in dilute aqueous solution, an extincition coefilcient of lessthan 0.25 for light having a wavelength of 400 millimicrons.

Colloidal suspensions are. more or lesscloudy to visible light,depending upon the wavelength, the finer, the particles the clearer thesolution. Other factors, such as the relative refractive indices of theparticles with respect to the solvent or dispersion medium, of coursealso play a. role in determining the degree of turbidity, but, ingeneral, the appearance of the solution gives some indication of therelative size of the dispersed particles in any given system.

By comparing solutions of colloidal silica at' the same concentration ofSiOz, the relative transparency to light is an indication of the type ofparticles present. However, by working with monochromatic light and bymeasuring the percentage of light transmitted through a solution ofgiven depth at a given concentration of silica, there can be calculateda constant, known as the extinction coefficient.

By a combination of Beers and Lamberts law, the following formula can bearrived at:

E}7,,,,=extinction coeificient p=per cent by weight of Sit); in thecolloidal solution L=length of adsorption cell in centimeters Iq=l00,taking the transmission of the dispersion medium, water, to be 100 Iobserved transmission of light of a given wavelength as compared to thetransmission of pure water.

It will be noted that the extinction coefficient for: a given type ofsolution isa constant which isindep'endent of the concentration ofthesolutiona'nd of the length of the cell through which the lightpasses, but the numerical value depends upon the manner in which theconcentration of the solution is expressed and uponthe unitin which-thelength of the cell'ismeasured. In this. case, the extinction coefiicientis givenin' terms ofthe percentage by weight of silica in solution andin terms of centimeters of cell length.

'Since light consists of electromagnetic waves, it is, of course,important to choosea wavelength such that the colloidal particlesinvolved will have some action on the waves. For example, if one choseto use infra-red light, it is possible that colloidal solutions ofsub-microscopic particles might be almost equally transparent, while ifa very short wavelength in the ultra-violet range See Gibb. lsted,OpticalMethodS of Analysis," page 73 t'.seq.'(1942)v V 1 tta? 810 where8 were used, relatively small, differences. in particle size would makea considerable difierence in the relative percentage transmission oflight through the two solutions being compared. It has been found thatcolloidal solutions of silica having an ultimate particle size less than0.03 micron can be distinguished from colloidal solutions of silicahaving particle considerably larger than this figure, by comparing themwith ultra violet light having awavelength of'400 millimicrons.

It has been found according to this invention. that colloidal solutionsof silica having an extinction coefficient of lessthan 0.25 areespecially useful for incorporating into aqueous dispersions of wax.

The proportion of colloidal silica used in an aqueous dispersion of thisinvention maybe considerably varied, depending. upon the use for whichthe composition is intended. In paste waxes of. the rub-to-polish type.containing from 20 to 40% wax the wmposition may contain up to about 18%by weight of colloidal silica, calculated as 8102- In the aqueous.dispersions of the self-polishing type, containing from about 10 to 15%of wax, the colloidal silica is preferably in the range of about 3 to 9%by weight, calculated as $102.

Th aqueous wax dispersions of this invention may be prepared accordingto methods with which the art is familiar and will ordinarily con--METHOD I This is perhaps the simplest and most easily controlled method,but its use is limited to the more easily dispersed waxes, such ascarnauba, montan, candelilla, etc.

The wax to bedispersed is placed-in the beaker which is immersed in thesteam bath (to prevent wax caking on the sides) and melted. The oleicacid can be melted along with the wax, can be added when half the wax ismeltedor after all the wax is melted, but in the present use theoleica-cid (or stearic acid), was added'when half the wax was melted.Meanwhile on aseparate hotplate the correct amount of water is broughtto the boiling point. To the melted wax is added the triethanolamine(morpholine,. etc.) and stirred thoroughly. To this is then addedtheboiling water and the mixture is vigorously stirred to form a smoothsuspension of wax in water. When potassium hydroxide and/or borax arecalled for in the formulation they canbe added to the water beforepouring into the wax or in the case of the dissolved potassiumhydroxide, it can be added immediately after the triethanolamine isadded. In the case of the test suspensions the colloidal silica is addedto the water before the latter is added to the melted Wax.

IVIETHOD II [0. ll. Bennett, Commercial Waxes, pages 409 to 470.]

In this method, the wax or oil is emulsified by means of a watersolution of the soap which is made from triethanolamine and stearic acid(or,

temperature is raised to just below the boiling point. The wax is nowmelted in a separate container and its temperature brought'to 85-95 C.This is then added to the water solution and the whole solution at oncestirred vigorously to obtain a gOOd emulsion. Stirring is then continuedgently until the product has cooled.

It should be noted that when the water is added to the wax care shouldbe exercisedsince a great amount of foaming is produced and the wax isdispersed with almost explosive violence. In the case of the testmixtures the colloidal silica was added to the water just before it waspoured into the wax.

METHOD III This was a modification of Method II. The potassiumhydroxide, triethanolamine, and oleic acid were added to the Water whichhad previously been dropped to 90 C. with rapid agitation. Inthemeantime the wax was brought to a temperature of l40150 C. The wax wasadded to the aqueous solution slowly with rapid agitation. After all thewax had been added the resulting suspension was stirred for fiveminutes. The suspension was then cooled for five minutes with noagitation and then the beaker was floated in a large pail of water untilcooled. Whil cooling the suspension was stirred occasionally to break upa thin crust which formed on the surface. When colloidal silica solutionwas present it was added to the water at the start of the preparaion. 1

' I METHOD IV This method was particularly eifective for dispersingsynthetic waxes. The dispersing agent and wax were placed in an aluminumbeaker, melted together, and the hot melt stirred with a drink mixer.This mixture was then heated to 140-150" C. on a hot plate. In the meantime the water was brought to a temperature of 90 C. and 30% of thewater was slowly added to the hot wax solution with rapid stirring. Theresulting emulsion was then slowly added to the remaining water at 90 C.This procedure was adopted because it gave extremely finely divided,stable dispersions of carnauba wax which dried to continuous, lustrousfilms.

The invention will be better understood by reference to the followingillustrative examples. In these examples, unless otherwise designated,the colloidal silica is sodium-stabilized, prepared by passing sodiumsilicate through an ion-exchange resin and concentrating the efiiuent bybatchwise constant volume evaporation to 30% SiOz by weight. The averagemolecular weight of this colloidal silica solution was about from 2 to 3million as determined by light scattering. The method used in preparingthe aqueous wax dispersions in each example is designated by Romannumerals I, II, III, or IV which refer to the methods as describedabove. In each example a comparable control formulation was prepared ina similar manner except that the colloidal silica was omitted with anappropriate compensation in the water content.

Example 1 This is an example of an aqueous dispersion containing anester type wax and colloidal silica prepared according to Method I. Anaqueous dispersion of wax containing colloidal silica suitable for useas a self-polishing floor wax was made up with the following componentsin the indicated proportions by weight:

Per cent Component By Weight g of Total Oarnaubo, wax (No. 3 N C 40. 013. 64 Clriethanolamine- 4. 0 1. 36 Oleic acid 3. 0 2. 73 Potassiumhydroxide KOH) 0. 5 l7 WVater 186. 7 76. 50 Colloidal silica, 30%aqueous soln 53. 3 5.46 (as SiO;)

Example 2 Anaqueous wax dispersion containing colloidal silica was madeup according to Method II containing the following components:

a Per cent Parts By Com onent By Weight p Welght of Total Carnauba wax(No. 2 N. O.) 43.5 15.64 Stearic acid 4. 5 1.62 Triethanolamine. 2. 0 0.72

ater 169. 7 75. 6

Colloidal silica, 30% SiOz 57. 8 f5. 26 (as S101) The dispersion thusobtained had a pH of 8.19 and a viscosity of 1'76 centipoises at 33.5 C.

The aqueous dispersion obtained was found to be suitable as aself-polishing floor wax on a linoleum floor, giving a high luster andbeing substantially skid resistant as compared with the control preparedin a similar manner except omitting the silica.

Example 3 In this example another type of ester wax, namely, beeswax,was used. An aqueous wax dispersion containing colloidal silica was madeup according to Method I containing the following components: I

Per cent Parts By Component 1 3y Weight elght of Total Beeswax (yellow)44 17.6 Oleic acid 4. 5 2. 0 Triethanolamine. l. 5 7 Water I 119. 3 70.3 Colloidal silica, 30% aqueous s 58. 5 7. 2 i l (as $102) Thedispersion thus obtained had a pH of 7.51, a viscosity greater-than 400centipoises at 34 C. and a surface tension of 42 dynes/cm. at 25 C.

When this composition was applied as a thin coating to linoleum it wasfound to dry to a lustrous coating without rubbing but the coating wasimproved upon bufiing. In comparison the coating prepared from a similarcomposition from which the silica had been omitted was relativelylacking in luster. A coating from the wax containing silica was alsofound to be remarkably resistant to slipping, being much improved inExample 4 This is-an example of still anotherester-type wax which isimproved by the addition of colloidal silica. This composition wasmadeup according to Method '1 and contained the follow- Sing-componentsParts By cent Component By Weight Weight of Total Candeli-llawax (doublerefined) 40.0 8. 2 Ol'eic' acid :6. n 1. 3 Triethanolaniine 8. 0 1. 7Water 351. 8 84. 8 Colloidal silica, 30% SiO 53.2 3. i (as SiO Thedispersion thus obtained had a pH of 8.07, a Viscosity of 4.1centipoises at 34 C., and a surface'tension of 40.6 dynes/cm. at 25 C.

When applied as a thin coating to a linoleum floor this composition wasalso found to dry to a lustrous coating without rubbing and the coatingwas found to be slip resistant. By comparison a similar compositionwithout silica gave a coating which was definitely lacking in luster andwas very tacky and hence completely unsuitable as a floor coating.

Example-5 This is an example of a modification of a hydrocarbon waxdispersion by colloidal silica. The

dispersion was made up according to Method II and contained thefollowing components:

The dispersion thus obtained had a pH of 8.04, a viscosity of 18.4centipoises at 335 0., and a surface tension of 31.5 dynes/cm. at 25 C.

When the composition was applied as a thin coating to a linoleum floorand allowed to dry the surface thus obtained was found to have arelatively low luster, which however was improved by buffing. On theother hand, the skid resistance of the coating was very markedlyincreased as compared to a coating made from a similar compositionwithout silica. Also, it was noted that the composition containingsilica dried much faster than that Without silica. Without the silica,the wax coating was too soft to be buffed satisfactorily.

Example 6 Thisis an example of a modification of a hydrocarbon waxcontaining some saponifia'ble material, by means of colloidal silica. Anaqueous dispersion of the wax was made up according to 12 Method I andcontaining the following comonents:

. Per cont Component r f -By Weight ll eight om Montan wax (crude). .40.0 8. 2 Oleic acid 2.1 Triethanolamiue 16:0 353 Water 363; 8 '82. 4 Borax4.0 .8

hIlOidaJsilicaBO XSYO 53.2 8. 29

The dispersion thus-obtained had-a pH of 8.49, a viscosity of"3.3centipoises at 33.5 'C., and a surface tension of 36Adynes/cm. at=25'C.Coat ings made from this composition on linoleum floors were found tohave improved skid resistance and improved luster as comparedwithooatings made from asirnilar composition without colloidal silica.

Example 7 This is anexample of an aqueous dispersion-of still anotherester-type wax containing colloidal silica. The dispersion was made upaccording to Method 11 and contained the following components:

The dispersion thus obtained had-a pH of 7.59, a viscosity of 47.2centipoises at 32 G., and a surface tension of 32. 9 dynes/cm. at 25 C.

It was noted in the preparation of the -dispersion that the colloidalsilica aided indispersing the wax, and produced a more uniformlydispersed wax of smaller particlesize than was obtained when the silicawas omitted.

A coating .madefrom the composition on linoleum was found to havesubstantially improved skid resistance ascompared toa similar coatingmade from aco'mposition whichwas identical'except that the silica wasomitted.

Examine 8 This is an example of an aqueousdispersion containingcolloidal silica and still another hydrocarbon-type wax. It was .made upaccording .to Method .IIand contained the following components:

This composition, when applied to linoleum, gave a coating whichwasdefinitely slip resistant as compared with a coating made from asimilar composition without the colloidal silica.

Example 9 This is an exampleof an aqueous dispersion containingcolloidal silica and a wax which is usually classified with theester-type waxes but 13 which is chemically sometimes classified as afat, namely, japan wax. This dispersion was prepared according to MethodIII and contained the following components:

This is anexample of a paste wax containing colloidal silica and asynthetic wax which is a complex nitrogen derivative of a higher fattyacid. This synthetic wax is known as acrawax, the wax used having thefollowing characteristics as described in trade bulletins entitledChemi- Q cals Glyco published by Glyco Products Co., copyright 1942 and1945: Acrawax is a hard, light brown, high luster synthetic wax having amelting point of 95 to 97 0., a flash point of 230 C. (open cup), aspecific gravity of'1.04 at 24 C. and .923 at the melting point, and asaponification value of 49. It is insoluble in cold water, completelysoluble in hot alcohol, hot butyl acetate, and hot turpentine. It iscompletely soluble in hot toluol and partially soluble in hot naphthabutforms a gel on cooling in both cases. It is also soluble in hot mineraloil or hot vegetable oil. The aqueous wax dispersion containingcolloidal silica was made up according to Method III and contained thefollowing components:

Per cent Parts By Coin onent Y Bv Weight p eight Total 40. 12. 18 4. 0l. 23 S. O 2. 44 0.

2. er 222. 2 79. l Colloidal silica, SiOz 53. 2 i. 88 (as S101) Thedispersion thus obtained was a paste. As compared to a control Withoutsilica this composition, when applied to a linoleum floor was found tohave substantially shortened drying time, somewhat improved slipresistance, and a slightly better luster. It was noted that the degreeof dispersion of the wax was greatly improved when the silicawaspresent.

Example 11 This is another example of a synthetic poly,

meric wax, the usefulness of which in aqueous dispersion is increased bythe addition of colloidal silica. The wax was a telomer of theethylenedichloracetic acid type. low pressure telomerization of ethylenewith dichloracetic acid as described in Hanford and Joyce United StatesPatent 2,440,800, issued May 4, 1948. More particularly, the wax wasprepared by a process of Example XII of said patent ex- It was preparedby the cept that the charge to the autoclave was 20 parts by weight of.dichloroacetic acid, 160 parts of water, and 0.6 part of benzoylperoxide, the ethylene pressure average 950 atmospheres, and thetemperature average 120 C. The telomer was a waxy solid, containing3.47% chlorine, equivalent to 67 ethylene units per dichloroacetic acid.I

The aqueous silica-wax dispersion wasmade up with the followingcomponents in the indicated parts by weight:

Component 33213;

Synthetic wax 3. 4 Beeswax 1. 7 Ceresin wax. l. 7 Turpentine. 3. 0 Naplitha 2. 7 Stearic acid 0. 9 Triethanolamine 1. 0 Colloidal silica,30% SiOL. 7. 4

The waxes and stearic acid were melted together and the triethanolamineadded. This mixture was heated to C. and the naphtha and turpentine wereadded to the resulting hot mixture at such a rate that a clear solutionwas maintained throughout the addition. The colloidal silica solutionwas then heated to boiling and poured in with vigorous stirring toproduce a smooth emulsion. Stirring was continued until the dispersionhad set to a firm gel.

As compared to a similar composition made without colloidal silica, thecomposition of the present example was found to give coatings onlinoleum floors which had improved skid resist ance and improved luster.

It was noted that other ethylene telomers such as those of ethylene andbromacetic acid, dioxolane, and pentachloroethylbenzene also gaveaqueous dispersions which were improved by the inclusion of colloidalsilica.

Example 12 While ester-type waxes are sometimes used alone in waxpolishes, the preferred waxes are usually so expensive that incommercial practice lower cost blends are used. This example is anillustration of the efiectiveness of colloidal silica in improving theluster and slip resistance of a blend of ester type waxes.

An aqueous dispersion was made up according to Method I using thefollowing components:

. Percent by Par ts by Component weight gvfilagtlltl Carnauba wax (N o.2 North Country) 20. 0 4. 42 Candelilla. wax (double refined) 20. 0 4.42 Oleic acid. (l. 0 1.32 'Iriethanolaminc 8. 0 1. 77 Borax 4. 0 88Water 342. l 83. 8 Colloidal silica 30% SiOz 53. 2 3. 54 (as SiOa)EMMFZBJB fi h s an examp e of the improvement of an aqueous waxdispersion by means of a differ n ing to 'Method III and contained thefollowing components:

. Per cent Component By Weight g of Total Carn'auba wax (No. 2 NorthCountry) 10. 11.73 flriethanolaminc 4. 0 l. 18 Qleic acid." 8.0 2.30Potassium by 0. 5 "Water 185.1 7.9.4 "Colloidal silica 15.0% SiOz 102. 64. 54 (as SiOz) The dispersion had a'pI-I of 8.16, a'vi'scosity of 17.19centipoises at 335 C. and a surface tension 01132. 1 .dynes/cm. at 2.5"C.

When the solutionwas applied as a thin coating to linoleum floors it-wasfound to give a film which upon drying was substantially improved "withrespect to slip resistance and luster as compared with a controlcontaining no silica.

Example 14 A typical commercial wax emulsion used for polishing floors,furniture, automobiles, etc, was modifiedhy adding about 15 parts of an18% solution of sodium-stabilized colloidal silica to 100 parts of thewax dispersion. The mixture was then applied to one-half of 'thetopof anautomobile in the usual manner, the other half of the aul'mnobile waswaxed with the unmodified wax .5,

emulsion. After daily exposure to summer weather and three washings withan anionic type wetting agent, it wasnotedzthat the surface Which hadbeen waxed with the silicaecontaining formulation remained hydrophobic,showing the continued presence ofa protective waxcoating, while thesurfacewhich .had been waxed with the unmodified formulation could bereadily wetted by water, indicating that no protective wax layerremained.

I claim:

1. A wax emulsion polishing composition 'com prising an aqueous waxemulsion and silica, the silica being in the form of dispersed particleshaving :a particle size of 1 to 100 millimicrons and in an amountsufiicient to impart skid resistance to a dried film of the composition.

2. A wax emulsion polishing composition comprising an aqueous ester-waxemulsion and silica.

the silica being in the form of dispersed particles having a particlesize of 1 to 100 millimicrons and in an amount suflicient to impart skidresistance to a dried film of the composition.

8. A wax emulsion polishing composition comprising :an aqueous .carnaubawax emulsion and silica, *the silica being in the form of dispersedparticles having a particle size of .1 .to millimicrons and in an amountsuflicient to impart skid resistance to:a dried film of the composition.

4. A wax emulsion polishing composition comprising an aqueous waxemulsion and silica, the

silica being in the form of dispersed particles having an averageultimate particle size of 1 .to 30 .millimicrons and in an amountsufficient to impart skid resistance to a dried filmof the :com-

position.

5. A wax emulsion polishing composition comprising an aqueous waxemulsion and silica, the silica beingin the iorrn of dispersed particleshavinga particle size of 1 to 100 millimicronsand in an amountsufficient to impart skid resistance to a dried film of the composition,and the silica, as an aqueous dispersion without the wax present, havingan extinction coefficient of less than 0.25.

6. A wax emulsion polishin composition comprising an aqueous waxemulsion, containing about 10 to 15% by weight'of wax, and about 3 to 9%by weight of silica, calculated as S102, the silica being in the form ofdispersed particles having a particle size of l to I00 millimicrons.

7. A wax emulsion polishing composition comprising an aqueous ester-waxemulsion and silica, the silica being in the form of dispersed particleshaving an average ultimate particle size of l to 30 millimicrons and inan amount sufficient to impart skid resistance to a dried film of thecomposition, and the silica, as an aqueous dispersion without the Waxpresent, having an extinction coefficient of less than 0.25.

8. A wax emulsion polishing composition comprising an aqueous ester-waxemulsion, containing about 10 to 15% by weight of wax, and about '3 to9% by Weight of silica, the silica being in the form of dispersedparticles having an average ultimate particle size of 1 to 3'0millimicrons and the silica, as an aqueous dispersion without the waxpresent, having an extinction coefiicient of less than 0.25.

RALPH K. ILER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,774,665 Pierce Sept. 2, 19302,244,325 Bird JuneB, 1941 2,374,474 Dolian Apr. 24, 1945 2,408,654 KirkOct. 1., 1946 2,432384 .Moulton Dec. 9, 194

FOREIGN PATENTS Number Country Date 407,028 Great Britain Mar. 3, 1934

1. A WAX EMULSION POLISHING COMPOSITION COMPRISING AN AQUEOUS WAXEMULSION AND SILICA, THE SILICA BEING IN THE FORM OF DISPERSED PARTICLESHAVING A PARTICLE SIZE OF 1 TO 100 MILLIMICRONS AND IN AN AMOUNTSUFFICIENT TO IMPART SKID RESISTANCE TO A DRIED FILM OF THE COMPOSITION.